The House Ethics Committee said Wednesday that it has cleared itself of wrongdoing during the buildup to the canceled ethics trial of Rep. Maxine Waters (D-Calif.) after a nearly yearlong investigation by a specially hired outside counsel.

The announcement that the committee unanimously concurred that Waters’ due process rights had not been violated clears the way for the committee’s case against the California Democrat to proceed.

A letter from acting Ethics Chairman Bob Goodlatte (R-Va.) and ranking member John Yarmuth (D-Ky.) to Waters that accompanied the committee’s announcement addressed each charge of misconduct that she made against the committee.

Though the committee allowed that one of its former staffers had likely leaked confidential information regarding the Waters case and made racially insensitive remarks during the investigation, it did not violate Waters’ rights, the committee said.

“The outside counsel has concluded, and the Committee has unanimously found that you have been afforded notice and the opportunity to be heard,” the letter said. “As such, there has been no violation of due process rights to which you are entitled. Even when the allegations are considered in their totality, there is still no violation of due process which you are due, and the Committee is entitled to continue its consideration of your matter.”

A representative from Waters’ office said the lawmaker was consulting with legal counsel before issuing a statement.

Wednesday’s announcement was the latest twist in a convoluted ethics investigation of the 11-term lawmaker that has dragged on for almost three years.

The probe began in the independent Office of Congressional Ethics, which in July 2009 voted unanimously that the Ethics Committee should review allegations that when Waters asked Treasury Department officials in September 2008 to meet with members of the National Bankers Association, it was primarily to discuss OneUnited Bank. Waters’ husband has in the past been a board member of the bank and had a financial stake in it at the time of the meeting.

The committee convened an investigative subcommittee in October 2009 to look into whether the meeting was a conflict of interest. In August 2010, it said that an adjudicatory subcommittee had been appointed to hear the case, and Waters was later scheduled for a rare public ethics trial in November of that year.

But the trial never happened.

Just 10 days before it was slated to begin, the committee announced that “due to materials discovered that may have had an effect on the investigative subcommittee’s transmittal” it would be sending the case back to the investigative subcommittee. Two committee staffers were placed on administrative leave, and documents leaked to the media showed that the committee’s former staff director believed the staffers might have acted improperly and compromised the investigation.

The committee announced in July 2011 that it had hired litigator Billy Martin as an outside counsel to review Waters’ charge that the committee had violated her rights during its investigation before deciding whether the case against her could proceed.

“Serious allegations have been made about the Committee’s own conduct in this matter by Representative Waters and others,” Ethics Chairman Jo Bonner (R-Ala.) and ranking member Linda Sánchez (D-Calif.) said in a joint statement issued at the time. “A thorough review of all of these serious allegations will be the very first task of the outside counsel’s engagement. … Outside counsel will then report his findings and conclusions to the full Committee, which will then determine whether the matter should proceed.”

Though Martin’s contract was set to expire Jan. 2, the committee announced in mid-December that it had reauthorized him to bill up to $500,000 for work on the Waters case through July 31, in addition to the $300,000 he had billed at that point under the terms of his original contract.

The committee announced in February that six of its members had voluntarily recused themselves from the Waters matter at Martin’s recommendation. Republican Reps. Mike Simpson (Idaho), Steven LaTourette (Ohio), Shelley Moore Capito (W.Va.), Tim Griffin (Ark.) and Goodlatte and Democratic Rep. John Sarbanes (Md.) were appointed as substitute committee members, with Goodlatte acting as chairman and existing Ethics member Yarmuth as ranking member. These members considered Martin’s findings.

Martin’s work with the committee could continue now that it has determined the case against Waters can move forward.

“Should the matter proceed, outside counsel will continue to make appropriate recommendations and provide appropriate assistance to the Committee to complete the matter as quickly as possible,” said the committee’s statement at the time of Martin’s hiring.

It was unclear Wednesday whether the committee’s announcement would affect the likelihood that Waters will succeed retiring Rep. Barney Frank (Mass.) as the top Democrat on the Financial Services Committee.

Rep. Carolyn Maloney (N.Y.), her chief rival for the seat, has said she will not challenge Waters.

Frank urged the Ethics Committee to conclude its investigation quickly.

“I would hope, now that they said they’re going forward, they would conclude in time for it to be resolved [and] not to be a factor one way or the other,” he said. “I think it would be a great mistake for them to have this drag out to a point where there was uncertainty by early next year.”

Daniel Newhauser contributed to this report.